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Capacitor Value Answered

Can someone identify the following


.05 +80%

Z5U 20%


Is this a .05uF capacitor rated at 1000volts?


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Jack A Lopez
Jack A Lopez

2 years ago

That is a good guess.

0.05 uF = 0.05 *(10^-6) F = 50*(10^-9) F = 50 nF

with max voltage of 1 KV = 1000 V

I can appreciate your skepticism though, since the scribbles printed on that thing kind of look like ancient hieroglyphics.

Also these tolerance numbers, plus 80% or minus 20%, are kind of wide. You might wonder why the distribution is so lopsided like that, more likely to be too high than too low. The story I have heard is for some applications, like for low pass filters, there is no harm in picking a capacitance a little too big, rather than too small.

What I say next might come as a surprise, but it turns out the best person, to actually identify that capacitor, is you!

The reason why is because you have it in your possession, and you can build a circuit for it, which could measure its capacitance.

Here I am guessing you do not have a test tool, like LCR meter,

because if you had one of those, you probably would have tried it on your mystery capacitor there, already.

Regarding a circuit that does something, depending strongly on capacitance, I suggest the old RC relaxation oscillator, made with 555 timer IC. I am guessing there is some combination of R and C, for your unknown C, that will produce an audible frequency.

Moreover if you wanted to accurately measure that frequency, you could record a sample of the audio, and examine it with some free audio editor, like Audacity.

Or these days, there might exist an ap, for your smart phone, that can do the same thing; i.e. identify the frequency of a tone it listens to.


2 years ago

See photo of capacitor?